I have to disagree with using definition lists in the gallery, a list of one does not make sense, either logically or how HTML is intended to be used.

For example, assistive technologies like screen readers provide navigation short-cuts for lists (and headings, links etc). So you would get to a gallery, and oh, it's a list, great. I'm not that interested in the list so you try and skip over it... to another list, and another etc.

The reason I re-opened this bug rather than just rely on [bug 6927] is that the 'itemtag' option doesn't allow you to use, for example, a proper list. I.e. where the gallery is a list (e.g. ul) and each item is a list item (li).

Would it be possible to change this to defining the top item (e.g. dl, ul, div), and have the function automatically pick the right per-image element? (e.g. dt, li, div).

At the moment I've hacked together a gallery shortcode replacement to output simplified code (including alt text), but it is a hack (I'm not a programmer), it would be better if the core could output accessible code by default.